WO2010090019A1 - Appareil de connexion, système de communication à distance et procédé de connexion - Google Patents

Appareil de connexion, système de communication à distance et procédé de connexion Download PDF

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Publication number
WO2010090019A1
WO2010090019A1 PCT/JP2010/000666 JP2010000666W WO2010090019A1 WO 2010090019 A1 WO2010090019 A1 WO 2010090019A1 JP 2010000666 W JP2010000666 W JP 2010000666W WO 2010090019 A1 WO2010090019 A1 WO 2010090019A1
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Prior art keywords
parameter
substream
downmix
combined
combining
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PCT/JP2010/000666
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English (en)
Japanese (ja)
Inventor
石川智一
則松武志
フアン ゾウ
シャン ジョン ハイ
コック セン チョン
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パナソニック株式会社
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Application filed by パナソニック株式会社 filed Critical パナソニック株式会社
Priority to US12/935,797 priority Critical patent/US8504184B2/en
Priority to CN201080001336.XA priority patent/CN102016982B/zh
Priority to JP2010532766A priority patent/JP5377505B2/ja
Publication of WO2010090019A1 publication Critical patent/WO2010090019A1/fr

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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
    • G10L19/008—Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities

Definitions

  • the present invention relates to a combining device, a telecommunication system, and a combining method, and in particular, a downmix substream obtained by downmixing a plurality of audio input signals and parameters for restoring the downmix substream into a plurality of audio input signals. And a combination apparatus for combining a plurality of encoded bit streams transmitted from each of a plurality of sites.
  • parametric coding technology has been very actively developed in the audio coding field because of its advantages of high coding efficiency and sound image reproduction.
  • parametric coding methods not only extend the limits of the human auditory system, but can also model audio input signals by capturing sound scene characteristics.
  • Technologies well known in the art include encoding methods related to parametric stereo and MPEG surround.
  • a typical parametric encoding apparatus 100 is shown in FIG.
  • a parametric encoding device 100 shown in FIG. 1 includes a TF (time-frequency) conversion unit 101, an analyzer 102, an FT (frequency-time) conversion unit 103, and a downmix encoder 104.
  • the TF converter 101 converts a plurality of audio input signals 110 that are time signals into a plurality of frequency signals 111.
  • the analyzer 102 analyzes the converted frequency signal 111 by two methods.
  • the analyzer 102 includes a downmix unit 102A and a parameter extraction unit 102B.
  • the downmix unit 102A generates a monaural or stereo intermediate downmix signal 112 from the plurality of frequency signals 111.
  • the parameter extraction unit 102B extracts parameters from the plurality of frequency signals 111, and outputs a parameter substream 113 including the extracted parameters.
  • the FT conversion unit 103 generates the downmix time signal 114 by inversely converting the intermediate downmix signal 112 into the time domain.
  • the downmix encoder 104 compresses the downmix time signal 114 and outputs a downmix substream 115 including the compressed signal.
  • the parametric encoded audio stream includes a downmix substream 115 and a parameter substream 113 corresponding thereto.
  • the parametric decoding device 200 includes a downmix decoder 201, a TF conversion unit 202, a parameter synthesis unit 203, and an FT conversion unit 204.
  • the downmix decoder 201 decodes the received downmix substream 115 into a monaural or stereo time signal 213.
  • the TF conversion unit 202 generates the frequency signal 214 by converting the time signal 213 again into the parametric analysis domain.
  • the parameter synthesis unit 203 generates a plurality of converted signals 215 by synthesizing the frequency signal 214 according to the information derived from the received parameter substream 113.
  • the FT converter 204 generates a plurality of audio output signals 216 by inversely converting the converted signal 215 into the time domain.
  • the plurality of audio output signals 216 perceptually represent the same spatial sound image as a single signal input.
  • the above encoding procedure shows two features of the parametric encoder. That is, they are the reconstruction of a realistic acoustic scene realized by the synthesis of spatially related parameters with high coding efficiency obtained from the reduction of the number of transmission channels.
  • Each communication site in such a system receives a plurality of audio input signals 110 from a plurality of speakers, and can usually expect an effect that a realistic presence can be obtained even in a remote place.
  • FIG. 3 is a diagram showing a remote communication system 300 including four remote conference sites 301A to 301D. Note that, when the sites 301A to 301D are not particularly distinguished, they are referred to as sites 301.
  • Each site 301 (eg, site 301A) employs a parametric codec.
  • the site 301 generates an encoded bit stream 116 (including a downmix substream Dmx A and a parameter substream Paras A ) by parametrically encoding all of the acquired audio input signals 110. Also, the generated encoded bit stream 116 is transmitted to the other three sites 301B to 301D.
  • each site 301 performs parametric decoding on the received encoded bitstream 116 (the encoded bitstream 116 includes three downmix substreams Dmx B , Dmx C , and Dmx D and three parameter substreams). Including Paras B , Paras C , and Paras D ).
  • a coupling device multipoint connection device: MCU 305
  • MCU 305 multipoint connection device
  • This MCU 305 combines a plurality of received encoded bit streams 116 into a single combined bit stream 124 for each site 301 in a computationally efficient manner. Ideally, the combined bitstream 124 should approximate the stream as if all of the multiple encoded bitstreams 116 from other sites 301 were encoded at a single virtual site. .
  • FIG. 4 is a block diagram illustrating a functional configuration of the MCU 305.
  • the MCU 305 includes three independent parametric decoders 401 to 403, an adder 404, and a parametric encoder 405.
  • the three parametric decoders 401-403 decode time for each site 301 (eg, site 301 A) by decoding all of the encoded bitstreams 116 from other sites 301 (sites 301 B, 301 C, and 301 D). Domain decoded signals 411B, 411C, and 411D are generated.
  • the addition unit 404 generates the addition signal 412 by adding the generated decoded signals 411B, 411C, and 411D.
  • the parametric encoder 405 generates the combined bit stream 124 by re-encoding the addition signal 412.
  • MCU 305 requires N independent tandem parametric decoding and encoding processes in a telecommunication system connecting N sites.
  • the calculation amount of the MCU 305 increases, and thereby the delay amount of signal transmission increases.
  • the amount of calculation increases linearly as the number of sites increases. Therefore, it is difficult for the MCU 305 to execute an application that requires real-time processing.
  • the audio stream format enables the ability to combine two or more streams into a single signal stream in a computationally efficient manner. More specifically, the downmix substream can be combined in the downmix coding domain, and the parameter substream can be combined in the parameter analysis domain.
  • Patent Document 1 proposes a method for efficiently combining a plurality of parametric encoded audio signals.
  • downmix coupling and parameter coupling are independent for the sake of simplicity.
  • the downmix coupling method only a biased method using a very rough coupling method is shown.
  • the parameter combination method a problem when using different parameter analysis domains is not addressed.
  • the parametric audio encoding method is preferred in actual communication systems because of its high encoding efficiency and sound scene reproduction characteristics. In order to realize this scenario, some practical issues must be addressed. That is, how to combine a plurality of parametrically encoded audio streams into a single stream with a low amount of computation.
  • an object of the present invention is to provide a coupling device that can reduce the amount of calculation.
  • a combining device includes a downmix substream in which a plurality of audio input signals are downmixed and transmitted from each of a plurality of sites, and the downmix substream.
  • a plurality of encoded bitstreams including a parameter substream for recovering a plurality of audio input signals, and effective within a predetermined time of the plurality of encoded bitstreams.
  • a detection unit that detects an active encoded bitstream that is an encoded bitstream, and a combination of only the plurality of downmix substreams included in the plurality of active encoded bitstreams among the plurality of downmix substreams.
  • a combined parameter substream is generated by combining only a plurality of parameter substreams included in the plurality of active encoded bitstreams among a plurality of parameter substreams and a first combining unit that generates a stream.
  • a second combining unit; and a transmission unit configured to transmit a combined bitstream including the combined downmix substream and the combined parameter substream to the plurality of sites.
  • the combining device does not perform combining processing on an inactive encoded bitstream.
  • the coupling device can reduce the amount of calculation by considering whether or not each site is active.
  • the first combining unit generates a plurality of decoded downmix substreams by decoding only the downmix substream included in the active encoded bitstream among the plurality of downmix substreams.
  • An adder that generates one or more intermediate combined downmix substreams by adding the plurality of decoded downmix substreams, and one or more by encoding the one or more intermediate combined downmix substreams
  • An encoding unit that generates the combined downmix substream.
  • the combining device does not perform decoding processing on an inactive encoded bitstream.
  • the coupling device can reduce the amount of calculation.
  • the first combining unit may transmit, to each of the plurality of sites, a plurality of downmix substreams included in the plurality of active encoded bitstreams transmitted from sites other than the site. Are combined with each other to generate a combined downmix substream corresponding to the site, and the second combining unit generates the plurality of active coding bits for each of the plurality of sites.
  • the transmitter is configured to combine the combined downmix substream.
  • an inactive coded bitstream that is a coded bitstream other than the active coded bitstream among the plurality of coded bitstreams.
  • the first combining unit generates a common combined downmix substream by combining a plurality of downmix substreams included in all active encoded bitstreams, and (1) 2)
  • the second combining unit generates a common combined parameter substream by combining a plurality of parameter substreams included in all active encoded bitstreams, and (3) the transmitting unit generates the common combined down stream.
  • Mix substream and the common connection Common binding bitstream containing a parameter sub-streams may be transmitted to the sender of the site of the two or more inactive coded bit stream.
  • the combining device when there are a plurality of inactive sites, transmits a common combined bitstream to the plurality of inactive sites.
  • the coupling device can reduce the number of times of coupling processing, thereby reducing the amount of calculation.
  • the transmission unit keeps the first encoded bitstream which is one of the two active encoded bitstreams as it is, and the two active encoded bits.
  • the second encoded bit stream that is the other side of the stream may be transmitted to the transmission source site, and the second encoded bit stream may be transmitted as it is to the transmission source site of the first encoded bit stream.
  • the combining device when there are two active sites, transmits the encoded bitstream transmitted from the active site as it is.
  • the coupling device according to one aspect of the present invention can reduce the number of times of coupling processing, thereby reducing the amount of calculation.
  • the transmission unit may transmit the active encoded bitstream as it is to a site other than the source site of the active encoded bitstream.
  • the combining device when there is one active site, transmits the encoded bit stream transmitted from the active site as it is.
  • the coupling device according to one aspect of the present invention can reduce the number of times of coupling processing, thereby reducing the amount of calculation.
  • the detection unit may detect the active encoded bitstream using information included in the plurality of parameter substreams.
  • the combining device can easily detect the active encoded bitstream using information included in the parameter stream.
  • the first combining unit generates the single combined downmix substream by combining the plurality of downmix substreams included in all active encoded bitstreams, and the second combining unit. Generates the single combined parameter substream by combining a plurality of the parameter substreams included in all active encoded bitstreams, and the transmitting unit generates the single combined downmix substream. And a single combined bitstream including the single combined parameter substream may be transmitted to all of the plurality of sites.
  • the combining apparatus further includes, for each active site that is a transmission source of the active encoded bitstream, out of the signal components of the single combined bitstream, the code transmitted by the active site.
  • An auxiliary information generation unit that generates auxiliary information for specifying a signal component corresponding to the coded bitstream may be provided, and the transmission unit may transmit each of the plurality of auxiliary information to a corresponding active site.
  • each site can exclude the signal component of the encoded bit stream transmitted by the own site using the auxiliary information transmitted by the coupling device according to one aspect of the present invention.
  • the auxiliary information generation unit identifies, for each of the active sites, a parameter corresponding to the parameter substream transmitted by the active site among parameters included in the single combined parameter substream.
  • the auxiliary information for generating may be generated.
  • each site can exclude the signal component of the encoded bit stream transmitted by the own site by updating the parameter using the auxiliary information transmitted by the coupling device according to one aspect of the present invention.
  • the second combining unit converts the parameter expression standards of the plurality of parameter substreams into a single unified parameter expression standard. Accordingly, a parameter standard unifying unit that generates a plurality of unified parameters may be provided, and the second combining unit may generate the combined parameter substream by combining the plurality of unified parameters.
  • the combining device can efficiently generate a combined parameter substream even when a plurality of parameter substreams are expressed by different parameter expression standards.
  • the combining device may further select a parameter criterion selection from the plurality of parameter expression criteria according to a current bit rate that can be used for transmission from the combining device to the plurality of sites. May be provided.
  • the combining device can efficiently integrate parameter substreams having different parameter expression criteria by considering the bit rate.
  • the combining device may further include a parameter reference selecting unit that selects the unified parameter expression criterion from a plurality of parameter expression criteria according to a bit cost indicating the number of bits of the combined parameter substream.
  • the combining device can efficiently integrate parameter substreams having different parameter expression criteria by considering the bit cost.
  • the downmix substream is encoded after the plurality of audio input signals are downmixed and converted to a spectral domain, and the decoding unit decodes the downmix substream.
  • the decoding downmix substream of the spectral domain is generated, and the adding unit adds the plurality of decoded downmix substreams of the spectral domain to add the one or more intermediate combined downmix substreams. It may be generated.
  • the combining device does not decode the encoded bitstream until the time domain. That is, the coupling device according to one embodiment of the present invention does not perform time-frequency conversion and vice versa. Thereby, the coupling device according to one embodiment of the present invention can reduce the amount of calculation.
  • the first combining unit may further include a scaling unit that scales the intermediate combined downmix substream so that spectral powers of the plurality of decoded downmix substreams are stored in the intermediate combined downmix substream.
  • the encoding unit may generate the combined downmix substream by encoding the intermediate combined downmix substream scaled by the scaling unit.
  • the combining apparatus can store the spectrum power of a plurality of decoded downmix substreams in the intermediate combined downmix substream.
  • the second combining unit generates a plurality of dequantization parameters by dequantizing a plurality of parameter substreams, and generates a combination parameter by combining the dequantization parameters.
  • a parameter combining unit that generates an update parameter by updating a part of the parameters included in the combined parameter, and a parameter other than the part of the parameters included in the combined parameter;
  • a quantization unit that generates the combined parameter substream by quantizing the update parameter.
  • the combining device combines and updates some of the parameters in the parametric analysis domain.
  • the parameters match the combining method of the downmix substream.
  • a telecommunications system includes a downmix substream obtained by downmixing a plurality of audio input signals, and a parameter substream for restoring the downmix substream to a plurality of audio input signals.
  • the combined bit stream is generated by combining a plurality of sites including an encoding device that generates an encoded bit stream including a plurality of encoded bit streams transmitted by the plurality of sites, and the generated combination And a combining device that transmits a bitstream to the plurality of sites, and each of the plurality of sites further includes a decoding device that generates an audio output signal by decoding the combined bitstream.
  • the telecommunications system according to an aspect of the present invention does not perform a combining process on an inactive coded bitstream.
  • the remote communication system according to an aspect of the present invention can reduce the amount of calculation of the coupling device.
  • a telecommunications system includes a downmix substream obtained by downmixing a plurality of audio input signals, and a parameter substream for restoring the downmix substream to a plurality of audio input signals.
  • the combined bit stream is generated by combining a plurality of sites including an encoding device that generates an encoded bit stream including a plurality of encoded bit streams transmitted by the plurality of sites, and the generated combination And a combining device that transmits a bitstream to the plurality of sites, each of the plurality of sites further including a decoding device that generates an audio output signal by decoding the combined bitstream, and the decoding
  • the device uses the auxiliary information to make the single connection. Of the signal components of the bit stream, to generate the audio output signal obtained by removing the corresponding signal component in the encoded bit stream transmitted by the site with the decoding device.
  • each site can exclude the signal component of the encoded bit stream transmitted by the own site using the auxiliary information transmitted by the coupling device.
  • the present invention can be realized not only as such a coupling device and a telecommunications system, but also as a coupling method that uses characteristic means included in the coupling device as steps, and such characteristic steps are performed by a computer. It can also be realized as a program to be executed. Needless to say, such a program can be distributed via a recording medium such as a CD-ROM and a transmission medium such as the Internet.
  • the present invention can be realized as a semiconductor integrated circuit (LSI) that realizes part or all of the functions of such a coupling device or telecommunications system.
  • LSI semiconductor integrated circuit
  • the present invention can provide a combining device that combines a plurality of parametric encoded audio streams while realizing a small delay and a small amount of calculation. This feature is very attractive for using a multi-site communication system such as a teleconference system for connecting a plurality of sites in real time.
  • FIG. 1 is a block diagram of a general parametric encoding apparatus.
  • FIG. 2 is a block diagram of a general parametric decoding device.
  • FIG. 3 is a diagram showing a configuration of a conventional telecommunications system.
  • FIG. 4 is a block diagram of a conventional MCU.
  • FIG. 5 is a diagram showing a configuration of the telecommunications system according to Embodiment 1 of the present invention.
  • FIG. 6 is a diagram showing parameter expression criteria in parametric audio coding according to Embodiment 1 of the present invention.
  • FIG. 7 is a block diagram of the downmix encoder according to Embodiment 1 of the present invention.
  • FIG. 8 is a block diagram of the MCU according to Embodiment 1 of the present invention.
  • FIG. 9 is a block diagram of a downmix substream combining unit according to Embodiment 1 of the present invention.
  • FIG. 10 is a diagram showing a frequency mapping method from the QMF domain to the MDCT domain according to Embodiment 1 of the present invention.
  • FIG. 11 is a block diagram of the parameter substream combining unit according to Embodiment 1 of the present invention.
  • FIG. 12 is a diagram showing the processing amount of the MCU according to the first embodiment of the present invention.
  • FIG. 13 is a flowchart of the combining process by the MCU according to the first embodiment of the present invention.
  • FIG. 14 is a diagram illustrating an operation when there is one active site of the MCU according to the first embodiment of the present invention.
  • FIG. 15 is a diagram showing an operation when there are two active sites of the MCU according to the first embodiment of the present invention.
  • FIG. 16 is a diagram showing an operation when there are three active sites of the MCU according to the first embodiment of the present invention.
  • FIG. 17 is a block diagram of an MCU according to Embodiment 2 of the present invention.
  • FIG. 18 is a diagram illustrating the operation of the MCU according to the second embodiment of the present invention.
  • FIG. 19 is a flowchart of the combining process by the MCU according to the second embodiment of the present invention.
  • FIG. 20 is a diagram showing the processing amount of the MCU according to the second embodiment of the present invention.
  • FIG. 21 is a block diagram of the parametric decoding apparatus according to Embodiment 2 of the present invention.
  • FIG. 22A is a diagram showing an example of parameter criteria according to Embodiment 2 of the present invention.
  • FIG. 22B is a diagram showing an example of parameter criteria according to Embodiment 2 of the present invention.
  • FIG. 23 is a block diagram of an MCU according to Embodiment 3 of the present invention.
  • FIG. 24 is a block diagram of a parameter substream combining unit according to Embodiment 3 of the present invention.
  • FIG. 25A is a diagram showing an example of a unified parameter criterion according to Embodiment 3 of the present invention.
  • FIG. 25B is a diagram showing an example of a unified parameter criterion according to Embodiment 3 of the present invention.
  • FIG. 25A is a diagram showing an example of a unified parameter criterion according to Embodiment 3 of the present invention.
  • FIG. 25B is a diagram showing an example of a unified parameter criterion according to Embodiment 3 of the present invention.
  • FIG. 25C is a diagram showing an example of the unified parameter criterion according to Embodiment 3 of the present invention.
  • FIG. 26A is a diagram showing parameter criteria according to Embodiment 3 of the present invention.
  • FIG. 26B is a diagram showing parameter criteria according to Embodiment 3 of the present invention.
  • FIG. 27 is a block diagram of an MCU according to Embodiment 4 of the present invention.
  • FIG. 28 is a block diagram of a parameter substream combining unit according to Embodiment 4 of the present invention.
  • the method using the MCU according to the present invention will be described below by taking a remote conference system (remote communication system) connecting four sites as an example.
  • An MCU for a remote conference system connecting more sites can be easily generalized from this case.
  • the combination of audio streams encoded by the conventional parametric encoding method will be described in detail.
  • the downmix signal is a monaural signal encoded by an AAC encoder.
  • the embodiments described below can be generalized to support other parametric encoded bitstream formats.
  • FIG. 5 is a diagram showing a configuration of the telecommunications system 300A according to Embodiment 1 of the present invention.
  • the remote communication system 300A is, for example, a remote conference system.
  • This telecommunications system 300A includes four sites 301 (301A to 301D) and a coupling device (MCU 305A) which is a multipoint connection device.
  • the four sites 301 and the MCU 305A are connected via a network.
  • Each site 301 includes the encoding device 100 shown in FIG. 1 and the decoding device 200 shown in FIG.
  • Each encoding device 100 performs a parametric encoding on a plurality of audio input signals 110 acquired by a plurality of microphones connected to the site 301, thereby encoding a downmix substream 115 and a parameter substream 113.
  • a generalized bitstream 116 is generated.
  • the downmix substream 115 is a signal obtained by downmixing a plurality of audio input signals 110
  • the parameter substream 113 is information for restoring the downmix substream 115 into a plurality of audio input signals.
  • each encoding device 100 transmits the generated encoded bit stream 116 to the MCU 305A.
  • each of the plurality of audio input signals 110 corresponds to the voice of each of a plurality of speakers.
  • the MCU 305A generates a combined bitstream 124 by combining a plurality of encoded bitstreams 116 transmitted by a plurality of sites 301.
  • This combined bitstream 124 includes a combined downmix substream 121 and a combined parameter substream 122.
  • the MCU 305A transmits the generated combined bitstream 124 to the plurality of sites 301.
  • the MCU 305A generates a combined bit stream 124 by combining the encoded bit stream 116 transmitted from a site other than the site 301 with respect to each site 301. Transmit to the site 301.
  • the MCU 305A combines the encoded bitstream 116 transmitted from the sites 301B to 301D with the site 301A, thereby combining the combined bitstream 124 (the combined downmix substream Dmx BCD and the combined parameter substream Paras BCD) . And the combined bitstream 124 is transmitted to the site 301A. Also, the MCU 305A generates a combined downmix substream Dmx ACD and a combined parameter substream Paras ACD by combining the encoded bitstream 116 transmitted from the sites 301A, 301C, and 301D with respect to the site 301B.
  • the MCU 305A generates a combined downmix substream Dmx ABD and a combined parameter substream Paras ABD by combining the encoded bitstream 116 transmitted from the sites 301A, 301B, and 301D with respect to the site 301C.
  • the MCU 305A combines the encoded bitstream 116 transmitted from the sites 301A, 301B, and 301C to the site 301D, thereby combining A stream Dmx ABC and a combined parameter substream Paras ABC are generated.
  • the decoding device 200 at each site 301 generates a plurality of audio output signals 216 by decoding the combined bitstream 124 transmitted from the MCU 305A.
  • the plurality of audio output signals 216 are output by a plurality of speakers connected to the site 301.
  • the encoding device 100 shown in FIG. 1 will be described in detail below.
  • the encoding apparatus 100 shown in FIG. 1 generates an encoded bit stream 116 including a monaural downmix substream 115 and a parameter substream 113 by parametrically encoding a plurality of audio input signals 110.
  • the encoding apparatus 100 includes a TF (time-frequency) conversion unit 101, an analyzer 102, an FT (frequency-time) conversion unit 103, and a downmix encoder 104.
  • the TF converter 101 converts a plurality of time domain audio input signals 110 into a plurality of frequency signals 111 in the hybrid domain.
  • T-F conversion unit 101 converts the N A number of audio input signals 110, with efficient non-uniform frequency resolution, the N A number of frequency signal 111 of the hybrid domain represented by the following (Equation 1) To do.
  • n is a time slot index indicating time.
  • K is a hybrid band index indicating a frequency.
  • the analyzer 102 analyzes the converted frequency signal 111 by two methods.
  • the analyzer 102 includes a downmix unit 102A and a parameter extraction unit 102B.
  • the downmix unit 102A generates a monaural intermediate downmix signal 112 from a plurality of frequency signals 111.
  • the parameter extraction unit 102B extracts object parameters from the plurality of frequency signals 111. Also, the parameter extraction unit 102B generates the parameter substream 113 by quantizing the extracted object parameters.
  • the parameter extraction unit 102B analyzes the object parameter as a time-frequency function with the resolution of the time frequency analysis determined based on the auditory psychological model. For example, the parameter extraction unit 102B groups the entire hybrid domain into P ⁇ Q parameter tiles as shown in FIG. Also, in order to approximate the frequency resolution of the human auditory system, the number Q of parameter bands m covering the entire frequency band is from only a few (when applying a low bit rate) to 28 (high). It can be set to any number in the case of quality processing. Also, the parameter set l separated to improve the transient behavior covers a fixed time segment (about 20-30 ms).
  • d i (l, m) is a predetermined scale factor for each audio input signal 110 (each frequency signal 111).
  • the factor e (l, m) is used for adjusting the power of the signal component. That is, the power of the signal component in the intermediate downmix signal 112 is calculated so as to be approximately the same as the power of the scaled full frequency signal 111. That is, e (l, m) is determined so that the relationship of the following (formula 3) is satisfied.
  • the FT conversion unit 103 generates a downmix time signal 114 by inversely converting all signal components of the intermediate downmix signal 112 into the time domain.
  • the downmix encoder 104 generates a downmix substream 115 by encoding the downmix time signal 114.
  • each of the object parameters includes:
  • Object level difference Indicates a power ratio in a corresponding parameter tile between a plurality of frequency signals 111.
  • Absolute energy parameter Indicates the absolute object energy of the frequency signal 111 having the maximum energy among the plurality of frequency signals 111.
  • Cross-correlation (IOC) between objects Indicates the similarity of corresponding parameter tiles between a plurality of frequency signals.
  • DMG Downmix gain
  • the parameter extraction unit 102B calculates these parameters using the following (formula 5) to (formula 9).
  • the parameter extraction unit 102B generates a parameter substream 113 by quantizing this object parameter together with other header information.
  • sites 301 also generate a downmix substream 115 and a corresponding parameter substream 113 according to a similar encoding procedure.
  • FIG. 7 is a block diagram showing a configuration of the downmix encoder 104.
  • the downmix encoder 104 includes an MDCT (Modified Discrete Cosine Transform) conversion unit 601, an encoding unit 602, and a control unit 603.
  • MDCT Modified Discrete Cosine Transform
  • the MDCT conversion unit 601 converts the downmix time signal 114 in the time domain into an MDCT coefficient set 611 in the MDCT domain (spectrum domain).
  • the control unit 603 calculates an estimated value of a masked threshold (acoustic psychology model) that depends on actual time using a rule known in acoustic psychology.
  • the encoding unit 602 efficiently quantizes and encodes the MDCT coefficient set 611 so that the quantization noise is kept below the masked threshold calculated by the control unit 603. Accordingly, the encoding unit 602 generates the downmix substream 115.
  • the encoding device 100 included in each site 301A to 301D needs to satisfy the following two additional requirements.
  • the downmix substream 115 is encoded by the AAC method using a fixed block type (that is, a long block type).
  • the present invention is not limited to this, and the AAC-LD method or the HE-AAC method may be used.
  • the CELP method may be used as long as it is a highly efficient stereo / monophonic audio encoding method, but this method is more effective when an encoding method using an orthogonal transform technique such as MDCT is used. The effect of the invention becomes higher.
  • the present invention is not limited to this, and the FFT method or the MDST (Modified Discrete Sine Transform) method may be used.
  • FIG. 8 is a block diagram showing the configuration of the MCU 305A.
  • the MCU 305A includes a detection unit 501, a downmix substream combination unit 504 (first combination unit), a parameter substream combination unit 506 (second combination unit), and a transmission unit 508.
  • the detection unit 501 detects an active site and an inactive site among a plurality of sites 301 within the time interval at predetermined time intervals.
  • the active site is a site that transmits a valid encoded bit stream 116
  • the inactive site is a site other than the active site.
  • an active site is a site where voice is currently being transmitted, and an inactive site is that voice is not currently being transmitted, a voice signal below a predetermined threshold is being exchanged, or It is a site that is explicitly designated by a control signal or the like when no audio signal is exchanged.
  • the maximum volume of the plurality of audio input signals 110 acquired at the active site is greater than or equal to a predetermined threshold, and all the volumes of the plurality of audio input signals 110 acquired at the inactive site are less than the predetermined threshold. .
  • the detection unit 501 detects whether each site 301 is an active site or an inactive site using information included in the plurality of parameter substreams 113. For example, the detection unit 501 determines that the transmission source site of the parameter substream 113 whose NRG parameter is less than a predetermined value is an inactive site.
  • the detection unit 501 may determine whether each site 301 is an active site or an inactive site by referring to other parameters or the downmix substream 115. For example, when the maximum volume of the plurality of audio input signals 110 included in the corresponding encoded bitstream 116 is equal to or higher than a predetermined threshold, the detecting unit 501 activates the transmission source site 301 of the encoded bitstream 116. When it is determined that the site is a site, and the maximum volume of the plurality of audio input signals 110 included in the corresponding encoded bitstream 116 is less than a predetermined threshold, the site 301 that is the transmission source of the encoded bitstream 116 is not You may determine that it is an active site.
  • the detection unit 501 determines that the source site 301 of the encoded bitstream 116 is the active site according to the volume difference or the change rate of the volume of the plurality of audio input signals 110 included in the corresponding encoded bitstream 116. Or inactive site may be determined.
  • the detection unit 501 calculates the number of active sites and the number of inactive sites based on the detection result.
  • the downmix substream combining unit 504 combines a plurality of downmix substreams 115 by combining the plurality of downmix substreams 115 according to the number of active sites (number of inactive sites) detected by the detection unit 501.
  • a stream 121 is generated.
  • the downmix substream combining unit 504 when there is an inactive site, the downmix substream combining unit 504 generates a combined downmix substream 121 by combining only the downmix substream 115 transmitted from the active site.
  • the downmix substream combining unit 504 transmits, to each of the plurality of sites 301, the sites 301 other than the site 301 among the plurality of downmix substreams 115 transmitted from the plurality of active sites.
  • the combined downmix substream 121 corresponding to the site 301 is generated by combining the plurality of downmix substreams 115 transmitted from.
  • the parameter substream combining unit 506 combines the plurality of parameter substreams 113 according to the number of active sites (the number of inactive sites) detected by the detecting unit 501, thereby combining the plurality of combined parameter substreams 122. Generate.
  • the parameter substream combining unit 506 when there is an inactive site, the parameter substream combining unit 506 generates a combined parameter substream 122 by combining only the parameter substreams 113 transmitted from the active site.
  • the parameter substream combining unit 506 transmits to each of the plurality of sites 301 from the sites 301 other than the site 301 among the plurality of parameter substreams 113 transmitted from the plurality of active sites. By combining the plurality of parameter substreams 113, a combined parameter substream 122 corresponding to the site 301 is generated.
  • the transmission unit 508 transmits the combined bitstream 124 including the combined downmix substream 121 and the combined parameter substream 122 to the corresponding site 301.
  • FIG. 9 is a block diagram showing a configuration of the downmix substream combining unit 504.
  • the downmix substream combining unit 504 includes a decoding unit 700, an adding unit 704, a scaling unit 705, and an encoding unit 706.
  • FIG. 9 shows a case where one combined downmix substream 121 to be transmitted to the site 301A is generated.
  • the decoding unit 700 decodes (decodes and dequantizes) the plurality of downmix substreams 115 (Dmx B , Dmx C, and Dmx D ), thereby corresponding to MDCTs in the MDCT domain (spectrum domain).
  • a coefficient set 710 (coef B , coef C, and coef D ) is generated.
  • inverse encoding and inverse quantization are inverse operations of AAC encoding performed by the encoding unit 602 shown in FIG.
  • Decoding section 700 also includes decoding sections 701 to 703 that decode and dequantize downmix substreams Dmx B , Dmx C, and Dmx D.
  • the decoding unit 700 includes three decoding units 701 to 703 as shown in FIG. 9, and three downmix substreams 115 may be processed in parallel by the three decoding units 701 to 703. Alternatively, one or two inverse encoding units may be provided, and the three downmix substreams 115 may be processed in a time division manner.
  • the decoding unit 700 decodes only the downmix substream 115 transmitted from the active site among the plurality of downmix substreams 115.
  • the addition unit 704 generates a combined MDCT coefficient set 711 (intermediate combined downmix substream) by adding all the MDCT coefficient sets 710 (decoded downmix substream).
  • the scaling unit 705 generates a combined MDCT coefficient set 712 (coef BCD ) by scaling the added combined MDCT coefficient set 711. Specifically, the scaling unit 705 scales the combined MDCT coefficient set 711 so that the spectral powers of the plurality of MDCT coefficient sets 710 are stored in the combined MDCT coefficient set 712.
  • the combined downmix substream 121 is obtained as a result of linearly combining all downmix substreams 115 with different combined gains in different frequency ranges.
  • the hybrid domain has time-frequency resolution, but the MDCT domain has only frequency resolution.
  • the coupling gain to the MDCT coefficient set, it is necessary to approximate the value in the hybrid domain to the value in the MDCT domain.
  • the approximation method applied in the present invention is a method of ignoring the separation of the parameter set in the hybrid domain and directly mapping the parameter band separation method to the MDCT domain (note that the separation method of different parameter bands is a single unified parameter). A method of integrating the band separation method will be described later).
  • the number of parameter bands used in the parametric encoding process is Q (header information included in the parameter substream)
  • the parameter band m covers the same frequency range as the subset I m , eg (q m ⁇ , q m + ).
  • the combined gain of the divided downmix coefficient set can be designed flexibly as follows according to different application examples.
  • Embodiment 1 when all of a plurality of encoded audio objects are important, neither amplification nor attenuation of signal components is preferable. In such a case, a power conservation technique that applies a common scaling factor for equalizing the combined downmix coefficients is employed.
  • the combined MDCT coefficient set coef BCD is expressed by the following (formula 8).
  • i is the MDCT coefficient index and m is the subset index. That is, i is expressed by the following (formula 9).
  • the superscript symbol represents the site index of the corresponding parameter.
  • the coupling gain is calculated using the following (Equation 10) so as to preserve the spectrum power.
  • the encoding unit 706 generates a combined downmix substream 121 (Dmx BCD ) for transmission by quantizing and encoding the combined MDCT coefficient set coef BCD .
  • perceptual encoders eg, AAC encoders
  • the downmix combination is performed only in the MDCT domain in order to satisfy the requirement that the calculation amount is small and the delay time is short. That is, any domain conversion from the MDCT domain to the time domain is not allowed.
  • the encoding unit 706 can be designed as follows. First, in the MDCT domain, an accurate psychoacoustic masker for the combined MDCT coefficient set is calculated. In addition, the remaining quantization and encoding are performed in a manner similar to the AAC encoder. The output result is transmitted as a combined downmix substream 121 to the parametric decoding device 200 at the site 301A. A similar procedure is performed for all other sites. That is, this procedure is performed N times for a system connecting N sites.
  • FIG. 11 is a block diagram showing the configuration of the parameter substream combining unit 506.
  • the downmix substream combination unit 504 includes an inverse quantization unit 750, a parameter combination unit 755, a parameter update unit 756, and a quantization unit 757. Further, FIG. 11 shows only a configuration for generating one combined parameter substream 122 to be transmitted to the site 301A.
  • the inverse quantization unit 750 restores the parameter substreams 113 (Paras B , Paras C, and Paras D ) to the corresponding parameters 761 by performing inverse quantization.
  • the inverse quantization is an inverse operation of the quantization performed by the parameter extraction unit 102B shown in FIG.
  • the parameter combining unit 755 generates combined parameters 763 and 764 by combining all the parameters 761.
  • the parameter update unit 756 generates the update parameter 765 by updating the combined parameter 764.
  • the parameter combining unit 755 combines all parameters 761 using the same coupling gain. As a result, this downmix combining process is not affected by additional parameters. Therefore, when there are a plurality of active sites, the parameter update unit 756 updates only the NRG parameter and the OLD parameter as the combined parameter 764.
  • the parameter substream combining unit 506 combines the parameter substreams 113 transmitted from the sites 301B and 301D.
  • the parameter update unit 756 calculates the updated OLD parameter for all objects using the following (formula 12).
  • the object indicates each of the plurality of audio input signals 110.
  • the quantization unit 757 generates the combined parameter substream 122 by quantizing the combined parameter 763 and the update parameter 765.
  • the MCU 305A needs to perform partial decoding processing N times, combining processing N times, and partial encoding processing N times.
  • the same combined downmix substream 121 is delivered to those inactive sites. In other words, when an inactive site normally exists, this means that the combining method is redundant.
  • the calculation amount of the MCU 305A is further reduced by considering the number of active sites before the combining and encoding process.
  • the transmission unit 508 directly switches and transmits the received encoded bitstream 116 to the distribution destination site. Thereby, the calculation amount of MCU305A can further be reduced.
  • the downmix substream combining unit 504 combines all the downmix substreams 115 transmitted from all active sites, thereby combining all inactive sites.
  • a common combined downmix substream 121 is generated for the site.
  • the parameter substream combining unit 506 generates a common combined parameter substream 122 for all inactive sites by combining a plurality of parameter substreams 113 transmitted from all active sites.
  • the transmission unit 508 transmits the common combined bitstream 124 including the common combined downmix substream 121 and the common combined parameter substream 122 to all inactive sites.
  • the transmission unit 508 transmits the encoded bit stream 116 transmitted from one of the two active sites as it is to the other of the two active sites. Also, the transmission unit 508 transmits the encoded bit stream 116 transmitted from the other of the two active sites as it is to one of the two active sites.
  • the transmission unit 508 transmits the encoded bit stream 116 transmitted from the active site to all inactive sites as it is.
  • FIG. 12 is a diagram showing a calculation amount of the MCU 305A according to the present invention and a normal MCU.
  • FIG. 13 is a flowchart of the combining process performed by the MCU 305A.
  • the detection unit 501 detects the number N 1 of active sites (S101).
  • the detection unit 501 determines whether the 1 (S102).
  • the transmission unit 508 transmits the coded bit stream 116 transmitted from the active site as it is to all inactive site (S103). That is, the downmix substream combining unit 504 and the parameter substream combining unit 506 do not perform combining processing. Also, the transmission unit 508 does not transmit the encoded bit stream 116 and the combined bit stream 124 to one active site.
  • the transmission unit 508 does not transmit the encoded bit stream 116 and the combined bit stream 124.
  • FIG. 14 is a diagram schematically illustrating the processing of the MCU 305 ⁇ / b> A when only one site 301 ⁇ / b> A is active among the four sites 301.
  • the MCU 305A transmits the downmix substream Dmx A and the parameter substream Paras A transmitted from the site 301A to the inactive sites 301B, 301C, and 301D.
  • the downmix substream coupling section 504 performs a partial decoding process into a plurality of downmix substream 115 sent from all active sites Thus, a plurality of MDCT coefficient sets 710 are generated (S104).
  • the detection unit 501 determines whether the 2 (S105).
  • the downmix substream coupling portion 504 by combining and scaling the MDCT coefficient sets 710 corresponding to the two active sites, binding MDCT coefficient sets 712 Is generated.
  • the downmix substream combining unit 504 generates one combined downmix substream 121 for inactive sites by encoding and quantizing the generated combined MDCT coefficient set 712.
  • the parameter substream combining unit 506 generates one combined parameter substream 122 for the inactive site by combining the parameter substreams 113 corresponding to the two active sites (S106).
  • the transmission unit 508 transmits one combined downmix substream 121 and combined parameter substream 122 generated in step S106 to all inactive sites (S107).
  • the transmitting unit 508 transmits the encoded bit stream 116 transmitted from one of the two active sites as it is to the other active site, and the encoded bit stream transmitted from the other active site. 116 is transmitted as it is to one active site (S108).
  • the binding process are one. That is, the partial decoding process for the inactive site is reduced, and the number of combining processes and the number of partial encoding processes are reduced to one.
  • FIG. 15 is a diagram schematically showing processing of the MCU 305A when only two sites 301A and 301B out of four sites 301 are active.
  • the MCU 305A transmits the downmix substream Dmx A and the parameter substream Paras A transmitted from the site 301A to the active site 301B, and the site 301B
  • the downmix substream Dmx B and the parameter substream Paras B transmitted from are transmitted to the active site 301A.
  • the MCU 305A combines the downmix substream Dmx A and the parameter substream Paras A with the downmix substream Dmx B and the parameter substream Paras B , thereby combining the combined downmix substream Dmx AB and the combined parameter substream.
  • Paras AB is generated, and the combined downmix substream Dmx AB and the combined parameter substream Paras AB are transmitted to the inactive sites 301C and 301D.
  • the downmix substream coupling portion 504 by any coupling and scaling the MDCT coefficient sets 710 corresponding to the three or more active sites, A combined MDCT coefficient set 712 is generated.
  • the downmix substream combining unit 504 generates one combined downmix substream 121 for inactive sites by encoding and quantizing the generated combined MDCT coefficient set 712.
  • the parameter substream combining unit 506 generates one combined parameter substream 122 for the inactive site by combining the parameter substreams 113 corresponding to the three or more active sites (S109).
  • the transmission unit 508 transmits one combined downmix substream 121 and one combined parameter substream generated in step S109 to all inactive sites (S110).
  • the MCU 305A generates a combined bit stream 124 to be transmitted to each of the three or more active sites.
  • the MCU 305A selects one active site from among three or more active sites, and generates a combined bit stream 124 to be transmitted to the selected active site.
  • the downmix substream combining unit 504 generates a combined MDCT coefficient set 712 by combining and scaling MDCT coefficient sets 710 corresponding to all active sites other than the selected active site.
  • the downmix substream combining unit 504 generates a combined downmix substream 121 for the selected active site by encoding and quantizing the generated combined MDCT coefficient set 712.
  • the parameter substream combining unit 506 generates a selected active site combined parameter substream 122 by combining the parameter substreams 113 corresponding to all active sites other than the selected active site (S111).
  • the transmission unit 508 transmits the combined downmix substream 121 and the combined parameter substream generated in step S111 to the selected active site (S112).
  • the downmix substream coupling unit 504 by subtracting 1 from the number N 1 of the active site, and calculate the number N 1 of a new active site (S113), the number N 1 of a new active sites If it is greater than 0 (Yes in S114), the next active site is selected, and the processing after step S111 is performed on the selected active site. That is, the downmix substream combining unit 504 repeats the processes of steps S111 to S114 for all active sites.
  • the number of partial decoding processes is as shown in FIG. number N 1 next to the number of number and partial encoding process for the joining process becomes N 1 +1 time. That is, the partial decoding process for the inactive site is reduced, and the number of the combining processes for transmission to the inactive site and the number of the partial encoding processes are reduced.
  • the processing of steps S109 and S110 are not performed. That is, as shown in FIG. 12, the number of partial decoding processes, the number of combining processes, and the number of partial encoding processes are N 1 times.
  • FIG. 16 is a diagram schematically showing processing of the MCU 305A when three sites 301A, 301B, and 301C among the four sites 301 are active.
  • the MCU 305A performs the downmix substream Dmx A and the parameter substream Paras A , the downmix substream Dmx B, the parameter substream Paras B, and the down A combined downmix substream Dmx ABC and a combined parameter substream Paras ABC are generated by combining the mixed substream Dmx C and the parameter substream Paras C , and the combined downmix substream Dmx ABC and the combined parameter substream Paras.
  • the MCU 305A combines the downmix substream Dmx B and the parameter substream Paras B with the downmix substream Dmx C and the parameter substream Paras C , thereby combining the combined downmix substream Dmx BC and the combined parameter substream.
  • a Paras BC is generated, and the combined downmix substream Dmx BC and the combined parameter substream Paras BC are transmitted to the site 301A.
  • the MCU 305A combines the downmix substream Dmx A and the parameter substream Paras A with the downmix substream Dmx C and the parameter substream Paras C , thereby combining the combined downmix substream Dmx AC and the combined parameter substream.
  • Paras AC is generated, and the combined downmix substream Dmx AC and the combined parameter substream Paras AC are transmitted to the site 301B.
  • the MCU 305A combines the downmix substream Dmx A and the parameter substream Paras A with the downmix substream Dmx B and the parameter substream Paras B , thereby combining the combined downmix substream Dmx AB and the combined parameter substream.
  • Paras AB is generated, and the combined downmix substream Dmx AB and the combined parameter substream Paras AB are transmitted to the site 301C.
  • the MCU 305A according to Embodiment 1 of the present invention does not perform the decoding process, the combining process, and the encoding process when the number of active sites N1 is 1 . Further, MCU305A, when the number N 1 of the active site is 2, does not generate a binding bitstream 124 to be transmitted to the active site. Thereby, MCU305A can reduce the amount of calculations.
  • the MCU 305A when there is an inactive site, does not combine the encoded bit stream 116 transmitted from the inactive site. Specifically, the MCU 305A does not perform the decoding process on the downmix substream 115 transmitted from the inactive site. Thereby, MCU305A can reduce the amount of calculations.
  • the MCU 305A when there are a plurality of inactive sites, the MCU 305A according to Embodiment 1 of the present invention generates a common combined bitstream 124 for the plurality of inactive sites. As a result, the MCU 305A can omit the process of generating the combined bit stream 124 for transmission to the inactive site, thereby reducing the amount of calculation.
  • the MCU 305A according to Embodiment 1 of the present invention can reduce the amount of calculation by taking into account the special case where the number of active sites is 1 or 2.
  • the partial encoding process includes an acoustic masker generation process and a double-loop quantization process, and thus has the largest amount of calculation. Therefore, the MCU 305B according to Embodiment 2 can further reduce the amount of calculation by performing partial encoding only once when there are a plurality of active sites (N 1 > 2).
  • FIG. 17 is a diagram showing a configuration of the MCU 305B according to the second embodiment of the present invention.
  • the MCU 305B illustrated in FIG. 17 is different from the MCU 305A according to Embodiment 1 in that the processing of the downmix substream combining unit 504B and the parameter substream combining unit 506B is performed by the downmix substream combining unit 504 and the parameter substream combining unit 506. It is different from processing.
  • the basic configurations of the downmix substream combining unit 504B and the parameter substream combining unit 506B are the same as those of the downmix substream combining unit 504 and the parameter substream combining unit 506.
  • the MCU 305B further includes an auxiliary information generation unit 507 in addition to the configuration of the MCU 305A.
  • the downmix substream combining unit 504B When the number of active sites is 2 or more, the downmix substream combining unit 504B generates a single combined downmix substream 121 by combining the downmix substreams 115 transmitted from all active sites.
  • the downmix substream combining unit 504B performs partial decoding processing on all active sites, and then combines all the decoded MDCT coefficient sets 710 into a single combined MDCT coefficient set 712. Next, the downmix substream combining unit 504B partially encodes the combined MDCT coefficient set 712 to generate a single combined downmix substream 121 that is distributed to all sites.
  • the parameter substream combining unit 506B When the number of active sites is 2 or more, the parameter substream combining unit 506B generates a single combined parameter substream 122 by combining the parameter substreams 113 transmitted from all the active sites.
  • the auxiliary information generation unit 507 generates a plurality of auxiliary information 123 corresponding to each active site.
  • the auxiliary information 123 identifies a signal component corresponding to the coded bitstream 116 transmitted by the corresponding active site among the signal components of the single combined downmix substream 121 and the single combined parameter substream 122. It is information to do.
  • the auxiliary information 123 will be described later.
  • the transmission unit 508 transmits the single combined downmix substream 121 and the single combined parameter substream 122 to all the sites 301. In addition, the transmission unit 508 transmits each of the plurality of auxiliary information 123 to the corresponding active site.
  • FIG. 18 is a diagram schematically showing processing of the MCU 305B when three sites 301A, 301B, and 301D among the four sites 301 are active in the telecommunications system 300B according to Embodiment 2 of the present invention. As shown in FIG.
  • the MCU 305B performs downmix substream Dmx A and parameter substream Paras A , downmix substream Dmx B and parameter substream Paras B , and down by combining the mixed sub-stream Dmx D and parameters substreams Paras D, and generates a combined down-mix sub-streams Dmx ABD and binding parameters substreams Paras ABD, the binding downmix substream Dmx ABD and binding parameters substreams Paras
  • the ABD is transmitted to all the sites 301A to 301D.
  • the MCU 305B transmits auxiliary information 123A, 123B, and 123D to the sites 301A, 301B, and 301D, which are active sites, respectively.
  • the auxiliary information 123A, 123B, and 123D are auxiliary information 123 corresponding to the sites 301A, 301B, and 301D, respectively.
  • FIG. 19 is a flowchart of the combining process of the MCU 305B according to the second embodiment of the present invention.
  • FIG. 20 is a diagram showing the amount of calculation between MCUs 305A and 305B according to Embodiments 1 and 2 of the present invention and a normal MCU.
  • steps S101 to S104 shown in FIG. 19 is the same as that in FIG.
  • the downmix substream combining unit 504B After step S104, the downmix substream combining unit 504B generates a combined MDCT coefficient set 712 by combining and scaling the MDCT coefficient sets 710 corresponding to all active sites. Next, the downmix substream combining unit 504B generates one combined downmix substream 121 by encoding and quantizing the generated combined MDCT coefficient set 712. Also, the parameter substream combining unit 506B generates one combined parameter substream 122 by combining the parameter substreams 113 transmitted from all the active sites (S205).
  • the transmission unit 508 transmits one combined downmix substream 121 and combined parameter substream 122 generated in step S205 to all sites (S206).
  • the number N 1 of the active site is two or more (No in S102), as shown in FIG. 20, the number of partial decoding process, the number N 1 becomes active site, the number of binding processing and The number of partial encoding processes is one. That is, the partial decoding process for the inactive site is reduced, and the number of combining processes and the number of partial encoding processes are reduced to one.
  • the calculation amount can be reduced to less than 15% with respect to a normal MCU.
  • the purpose of the MCU 305B is to combine the encoded bit stream 116 from all the sites other than the transmission destination site into a single combined bit stream 124 as described in the first embodiment. Therefore, as in the second embodiment, when the combined bitstream 124 is a combination of all the encoded bitstreams 116, each site 301 transmits the interference stream in the combined bitstream 124 (the encoding transmitted by itself). It is necessary to remove the component of the bit stream 116).
  • the MCU 305B generates a common combined parameter substream 122 including all parameter information. Further, each site 301 uses the common combined parameter substream 122 to mute the interference stream in the combined bitstream 124 in the parametric decoding process. Thereby, the telecommunications system 300B according to Embodiment 2 of the present invention realizes the removal of the interference stream in the parameter domain.
  • the common combined parameter substream 122 is constructed through the following steps.
  • the common combined parameter substream 122 is delivered to each site together with the common combined downmix substream 121.
  • the ultimate goal of parametric decoding at each site is to synthesize (ie, upmix) all audio inputs except for the input of the interfering stream from the site.
  • the end goal of parametric audio decoding can be achieved by customizing the drawing matrix. More specifically, in order to remove the interference object from its own site, some new auxiliary information 123 should be generated by the MCU 305B and transmitted to the receiving site.
  • the auxiliary information 123 is, for example, an index of an interference object.
  • the decoding device 200B provided at each site can set a zero gain to the interference object in the drawing matrix of the parametric audio coding. As a result, it is ideal if the interference object is muted.
  • the auxiliary information generation unit 507 sets the parameter corresponding to the parameter substream 113 transmitted by the active site among the parameters included in the single combined parameter substream 122.
  • the auxiliary information generation unit 507 uses the number of objects (N B ) and the start object index (N A +1) included in the common combined parameter substream 122 as the auxiliary information 123 together with the combined parameter substream 122 To the site 301B.
  • FIG. 21 is a block diagram showing a configuration of parametric decoding apparatus 200B provided in the site according to Embodiment 2 of the present invention. Elements similar to those in FIG. 2 are denoted by the same reference numerals, and redundant description is omitted.
  • a decoding device 200B illustrated in FIG. 21 further includes a parameter conversion unit 205 in addition to the configuration of the decoding device 200 illustrated in FIG.
  • the decoding apparatus 200B uses the auxiliary information 123 to remove the signal component corresponding to the encoded bit stream 116 transmitted by the site 301 including the decoding apparatus 200B from the signal components of the single combined bit stream 124.
  • the plurality of audio output signals 216 are generated.
  • the parameter conversion unit 205 is a drawing matrix having a size of N speaker ⁇ N total (N speaker represents the number of speakers in the site 301B) arbitrarily designed for subsequent parametric decoding.
  • N speaker represents the number of speakers in the site 301B
  • the matrix elements from column N A +1 to column N A + N B are set to zero. This means that the gain of all objects from N A +1 to N A + N B is zero in N speaker speakers.
  • the interference object at site 301B is muted and the remaining audio objects from other sites are played as desired.
  • the MCU 305B according to Embodiment 2 of the present invention can reduce the amount of calculation by generating only the single combined downmix substream 121 and the combined parameter substream 122.
  • the MCU 305B according to Embodiment 2 of the present invention generates auxiliary information 123 for each active site. Thereby, each site 301 can exclude the signal component of the coded bit stream 116 transmitted by the own site from the single combined downmix substream 121.
  • parameter substreams 113 from different sites may have different parameter representation criteria. This is because each site 301 can use different bit rates and express different object characteristics.
  • the MCU 305C according to the third embodiment of the present invention can support the combination of parameters expressed by different parameter expression standards.
  • the parameter expression standard is specifically a parameter tile dividing method (division interval).
  • two parameters substreams 113 for example, an example in which the parameter sub-stream Paras B from the site 301B, and a parameter sub-stream Paras C from the site 301C is input to MCU305.
  • the parameter substream Paras B is represented by a total of (P 1 ⁇ Q 1 ) parameter tiles for N 1 objects
  • the parameter substream Paras C is defined for N 2 objects. It is assumed that a total of (P 2 ⁇ Q 2 ) parameter tiles are used.
  • FIG. 23 is a block diagram showing a configuration of MCU 305C according to the third embodiment of the present invention.
  • symbol is attached
  • FIG. 24 is a block diagram showing the configuration of parameter substream combining section 506C according to Embodiment 3 of the present invention.
  • symbol is attached
  • FIG. 24 shows a case where the parameter substreams Paras B and Paras C are combined.
  • the parameter substream combining unit 506C illustrated in FIG. 24 further includes a parameter standard unifying unit 754 in addition to the configuration illustrated in FIG.
  • the parameter standard unifying unit 754 converts the parameter expression standards of the plurality of parameters 761 into a single unified parameter expression standard, A plurality of unified parameters 762 are generated.
  • the parameter combining unit 755 generates a combined parameter 763 by combining all the unified parameters 762.
  • the parameter standard unifying unit 754 integrates the parameter substreams having the hybrid parameter expression standard, the fine parameter band Q 1 out of the parameter bands Q 1 and Q 2 , and the parameter set P 1. And a fine parameter expression standard having a fine parameter set P 2 among P 2 can be adopted.
  • the parameter standard unifying unit 754 employs a fine standard using (P 2 ⁇ Q 1 ) tiles as a standard.
  • the parameter standard unifying unit 754 integrates the coarse parameter band Q 2 out of the parameter bands Q 1 and Q 2 , the parameter set P 1 and the parameter set P 1 in order to integrate the parameter substreams having the hybrid parameter expression standard. it can be employed parameter representation criteria moderate with a fine parameter set P 2 of P 2.
  • the parameter standard unification unit 754 employs a medium standard using (P 2 ⁇ Q 2 ) tiles as the uniform standard.
  • the parameter standard unifying unit 754 integrates the coarse parameter band Q 2 out of the parameter bands Q 1 and Q 2 , the parameter set P 1, A coarse parameter expression criterion having a coarse parameter set P 1 out of P 2 can be adopted.
  • the parameter standard unifying unit 754 employs a rough standard using (P 1 ⁇ Q 2 ) tiles as a standard.
  • parameter standard unifying unit 754 needs to expand or contract all the parameters of the standard different from the standard after the standardization until it corresponds to the standard after the standardization.
  • the parameter standard unifying unit 754 refines the parameter expression standard from the old large parameter tile standard to the new small tile standard, that is, from FIG. 26A to FIG. 26B. If the old tile (l, m) covers a new small tile from (l ', m') to (l '+ ⁇ l, m' + ⁇ m), the parameters defined for the old tile are replicated to the new tile. For example, the parameter standard unifying unit 754 calculates a new OLD using the following (formula 20).
  • parameters having other parameter types such as IOC, NRG and DMG can be refined similarly.
  • the parameter expression criterion is averaged from multiple old small tiles to one new large tile, ie from FIG. 26B to FIG. 26A.
  • different parameter types are averaged with different averaging methods.
  • the parameter standard unifying unit 754 can calculate a new NRG parameter on the tile (l, m) using the following (formula 21).
  • the parameter standard unifying unit 754 can calculate a new OLD parameter using the following (formula 22).
  • the parameter standard unifying unit 754 can calculate a new IOC parameter using the following (formula 23).
  • the parameter standard unifying unit 754 can calculate a new DMG parameter by using one of the following (Expression 24) and (Expression 25).
  • the parameter standard unifying unit 754 can calculate a new DMG parameter using the following (formula 25).
  • S (u, v) represents the area of tile (u, v).
  • the MCU 305C according to the third embodiment of the present invention can combine parameters expressed by different criteria.
  • FIG. 27 is a block diagram showing a configuration of MCU 305D according to the fourth embodiment of the present invention. Note that the same elements as those in FIG. 23 are denoted by the same reference numerals, and redundant description is omitted.
  • the MCU 305D illustrated in FIG. 27 further includes a parameter reference selection unit 502 in addition to the configuration illustrated in FIG. Also, the configuration of parameter substream combining unit 506D is different from parameter substream combining unit 506C shown in FIG.
  • the parameter criterion selection unit 502 selects one of a plurality of parameter expression criteria, and outputs a selection signal 511 indicating the selected parameter expression criterion to the parameter substream combining unit 506. For example, the parameter criterion selection unit 502 selects one of the three parameter expression standards (detailed parameter expression standard, medium parameter expression standard, and coarse parameter expression standard) shown in FIGS. 25A to 25C.
  • the parameter criterion selection unit 502 can use a criterion switching mechanism, for example, a current bit rate 510 that can be used for transmission from the MCU 305D to the plurality of sites 301, or a bit of the corresponding combined parameter substream 122. It can be decided according to the cost. This can be achieved through the following three steps.
  • the parameter criterion selection unit 502 sets a detailed parameter expression criterion. select. This is expressed as (Equation 26) below.
  • br represents the actual MCU delivery bit rate
  • b 0 represents a pre-defined high bit rate for combined stream delivery
  • b 1 represents a pre-defined low bit rate value
  • c is pre- Represents a defined threshold, eg, a real number between 1.5 and 2.0.
  • the parameter criterion selection unit 502 determines whether the bit rate condition allowed for MCU distribution is too strict or whether moderate bit consumption is reasonable. Testing. That is, the parameter criterion selection unit 502 determines whether or not the following (Expression 27) is satisfied.
  • the parameter criterion selection unit 502 selects a medium parameter expression criterion.
  • the parameter standard selection unit 502 selects a rough parameter expression standard as the unified parameter expression standard.
  • the parameter criterion selection unit 502 may select the parameter expression criterion based on both the bit rate and the bit cost, or may select the parameter expression criterion based only on one of the bit rate and the bit cost. .
  • FIG. 28 is a diagram illustrating a configuration of the parameter substream combining unit 506D. Elements similar to those in FIG. 24 are denoted by the same reference numerals, and redundant description is omitted. Further, in the remote conference system connecting four sites, it is assumed that there are three active sites 301A, 301B and 301D. FIG. 28 shows only a configuration for generating one combined parameter substream 122 to be transmitted to the site 301A.
  • the configuration of the parameter standard unifying unit 754D is different from that of the parameter standard unifying unit 754 shown in FIG.
  • the parameter standard unifying unit 754D generates a unified parameter 762 by converting a plurality of parameters 761 into the parameter expression standard indicated by the selection signal 511.
  • the MCU 305D according to Embodiment 4 of the present invention can efficiently integrate the parameter substreams 113 having different parameter expression criteria by considering the bit rate or the bit cost.
  • the downmix substream combining unit 504 or 504B described an example in which a plurality of downmix substreams 115 are combined in the MDCT domain (spectral domain).
  • multiple downmix substreams 115 may be combined in the time domain.
  • each processing unit included in the combining device, the encoding device, and the decoding device according to the first to fourth embodiments is typically realized as an LSI that is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them.
  • circuits are not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor.
  • An FPGA Field Programmable Gate Array
  • reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.
  • a processor such as a CPU executing a program.
  • the present invention may be the above program or a recording medium on which the above program is recorded.
  • the program can be distributed via a transmission medium such as the Internet.
  • the above-described coupling method using the coupling device is for illustrative purposes only, and the coupling method using the coupling device according to the present invention is not limited to the above.
  • the order in which the above steps are executed is for illustration in order to specifically describe the present invention, and may be in an order other than the above. Also, some of the above steps may be executed simultaneously (in parallel) with other steps.
  • the present invention can be applied to a coupling device. Further, the present invention can be applied to a remote conference system using the coupling device.

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  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
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  • Audiology, Speech & Language Pathology (AREA)
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Abstract

L'invention porte sur un appareil de connexion (305) qui comporte une unité de détection (501) qui détecte un train de bits codé actif qui est un train de bits codé effectif parmi une pluralité de trains de bits codés (116), en l'espace d'un temps prédéterminé ; une première unité de connexion (504) qui connecte, parmi une pluralité de sous-flux de mélange-abaissement (115), seuls ceux (115) contenus dans une pluralité de trains de bits codés actifs pour générer un sous-flux de mélange-abaissement connecté (121) ; et une seconde unité de connexion (506) qui connecte, parmi une pluralité de sous-flux de paramètres (113), uniquement ceux (113) contenus dans une pluralité de trains de bits codés actifs pour générer un sous-flux de paramètres connecté (122).
PCT/JP2010/000666 2009-02-04 2010-02-04 Appareil de connexion, système de communication à distance et procédé de connexion WO2010090019A1 (fr)

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CN201080001336.XA CN102016982B (zh) 2009-02-04 2010-02-04 结合装置、远程通信系统以及结合方法
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CN102016982A (zh) 2011-04-13
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